Page 12 of 68

AIRBAG - SEAT BELT PRETENSIONERS
Fault finding – Replacement of components
88C-12
88C
V3 MR-372-J84-88C000$040.mif
AIRBAG ACU4
VDIAG No.: 04
AIRBAG - SEAT BELT PRETENSIONERS
Fault finding – Replacement of components
REPLACING THE AIRBAG COMPUTER
BEFORE REPLACING ANY COMPUTER, YOU ARE REQUIRED TO CONTACT YOUR
TECHLINE.
So that the failure of the returned computer can be analyzed, the use of command RZ001
"erase fault memory" when DF001 "Computer" is present or stored is officially prohibited.
The airbag computers are sold in locked mode to avoid all risk of accidental triggering (all ignition lines are
inhibited).
The locked mode is signalled when the airbag fault warning indicator lights up on the instrument panel.
Follow this procedure to replace an airbag computer:
– Ensure that the ignition is switched off.
– Replace the computer.
– Modify the computer configuration if necessary.
– Enter the VIN into the computer with diagnostic tool command VP010 Write VIN.
– Switch off the ignition.
– Carry out a check using the diagnostic tool.
– Enter the After Sales operation date with diagnostic tool command VP008 Write last After Sales operation
date.
– Unlock the computer only if no faults are indicated by the diagnostic tool.
After an ACU4 computer has been replaced with a RC5 computer, it is also necessary to replace the impact
sensors. The ACU4 sensors are incompatible with the RC5 computer.
Note:
After the airbag computer is replaced, if the engine no longer starts, restore the injection operation by applying the
following procedure:
– Run command RZ001 to clear the faults from the injection computer memory (even if no present or stored faults
are declared).
– Switch off the ignition and wait for loss of dialogue with the injection computer.
– Drive for 1 minute at a speed greater than 21 mph (35 km/h) to restore the operation of the steering column lock.
ACU4 Vdiag04 J84 1.0

Page 13 of 68

AIRBAG - SEAT BELT PRETENSIONERS
Fault finding - Configuration and programming
88C - 13
88C
V3 MR-372-J84-88C000$050.mif
AIRBAG ACU4
Vdiag: 04
AIRBAG - SEAT BELT PRETENSIONERS
Fault finding - Configuration and programming
CLEARING
RZ001: Fault memory.
This command is used to clear faults from the computer's memory.
CONFIGURATION / READ CONFIGURATION:
– To make it easier to configure airbag computerACU4, the fault-finding tool has five automatic
configuration commands for the trigger lines and sensors installed in the vehicles (BMXX, CMXX,
SMXX).
The commands in the table on the next page, however, are used to configure each system
component individually to adapt the computer configuration to the actual equipment in the
vehicle.
– The read-configuration commands (LCXXX) are used to display the current computer configuration
in relation to the trigger lines and sensors installed in the vehicle.
– The configuration commands (CFXXX) are used to adjust computer configuration to the equipment
actually installed in the vehicle.
– STANDARD CONFIGURATION COMMANDS:
–CF297: B/C NO SIDE AIRBAGS.
Vehicle types B, C WITH NO FRONT AND REAR FRONTAL SIDE AIRBAGS AND NO SIDE
CURTAIN AIRBAGS (SABLAT / SSABCS).
–CF298: B/C WITH FRONT FRONTAL + CURTAIN AIRBAGS.
Vehicle types B, C with FRONT FRONTAL SIDE AIRBAGS + SIDE CURTAIN AIRBAGS
(ABLAVI / SSABCS).
–CF299: B/C WITH FRONT/REAR FRONTAL + CURTAIN AIRBAGS.
Vehicle types B, C with FRONT AND REAR FRONTAL SIDE AIRBAGS + SIDE CURTAIN
AIRBAGS (ABLAT / SSABCS).
–CF300: VAN WITH CURTAIN AIRBAGS.
Three S vehicles (vans) equipped with CURTAIN SIDE AIRBAGS (ABLAT / SSABCS).
–CF301: VAN WITH NO CURTAIN AIRBAGS.
Three S vehicles (vans) WITHOUT CURTAIN SIDE AIRBAGS (ABLAVI / SSABCS).
Because of probably computer part number unification in the Parts Department, some sensors
or trigger lines may have to be deconfigured after using standard configuration commands. For
this, use the individual configuration commands for system components.
After configuration, check the display configuration screen to make sure that the information
entered is correct.
ACU4 Vdiag04 J84 1.0
MR-372-J84-88C000$050.mif

Page 15 of 68

AIRBAG - SEAT BELT PRETENSIONERS
Fault finding - Configuration and programming
88C - 15
88C
V3 MR-372-J84-88C000$050.mif
AIRBAG ACU4
Vdiag: 04
CONFIGURATION / READ CONFIGURATION (continued):
Passenger airbag lock mode "WITH KEY" or "WITHOUT":
Read type of vehicle: LC034 "MEGANE II"
OTHER COMMANDS:
–VP006: Lock computer.
This command is used whenever servicing the system. It shuts down all trigger lines.
–VP007: Unlock computer.
This command unlocks the computer after it was locked.
–VP008: Write last After Sales service date.
This command is used to enter the date the system was serviced.
–VP010: Write VIN.
This command serves to enter the vehicle identification number (VIN) into the computer.
–SC004: Read impact context.
This command is used in reconditioning the vehicle following an impact. It obtains, from the
computer that is to be replaced, a list of the trigger lines controlled and the system's state at the
moment of impact.TITLECONFIGURATION
READINGCONFIGURATION
PASSENGER AIRBAG LOCK MODELC060 CF248
ACU4 Vdiag04 J84 1.0

Page 17 of 68

To be read with the diagnostic tool (Identification screen):
FAULT FINDING LOG
System: Airbag and pretensionersPage 2 / 2
●Identification of the computer and parts replaced for the system
Part 1 part no.
Part 2 part no.
Part 3 part no.
Part 4 part no.
Part 5 part no.
Computer part no.
Supplier no.
Program no.
Software version
Calibration number
VDIAG
●Faults found with the diagnostic tool
Fault no. Present Stored Fault title Specification
●
System-specific information
Total vehicle mileage (kilometrage) when the customer's problem
occurred:
How often does it occur?
How long after the engine starts?
●Additional information
What factors led you to replace the
computer?
What other parts were replaced?
Other faulty functions?
CAN
Wiring harness
SeatsInstrument panel
Battery
OtherRotary switch
Fuse
Please specify:
FD 16
Fault finding log
page to print or photocopy - page to print or photocopy - page to print or photocopy